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D.4.5.4 equiRadEHV
Procedure from library ehv.lib (see ehv_lib).
- Usage:
- equiRadEHV(I [,Strategy]); I ideal, Strategy list
- Return:
- ideal, the equidimensional radical of I,
i.e. the intersection of the minimal associated primes of I
having the same dimension as I
- Note:
- Uses the algorithm of Eisenbud/Huneke/Vasconcelos,
Works only in characteristic 0 or p large.
The (optional) second argument determines the strategy used:
Strategy[1] > strategy for the equidimensional part
= 0 : uses equiMaxEHV
= 1 : uses equidimMax
Strategy[2] > strategy for the radical
= 0 : combination of strategy 1 and 2
= 1 : computation of the radical just with the
help of regular sequences
= 2 : does not try to find a regular sequence
If no second argument is given then Strategy=(0,0,0) is used.
Example:
| LIB "ehv.lib";
ring r = 0,(x,y,z),dp;
poly p = z2+1;
poly q = z3+2;
ideal i = p*q^2,y-z2;
ideal pr= equiRadEHV(i);
pr;
==> pr[1]=z2-y
==> pr[2]=y2z+yz+2y+2
==> pr[3]=y3+y2+2yz+2z
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